Smoking tobacco products is habit forming. Prolonged smoking leads to a very strong addiction. The reasons it is so addictive are many. A most important element of the addictive process is the positive reenforcement of smoking provided by the pharmacologic action of the inhaled smoke. An important component of the inhaled smoke is the vasoactive alkaloid nicotine. This is inhaled into the lungs and promptly diffuses across the alveolar walls and into the pulmonary capillaries. Since the diffusion distance is of the order of a micron, it is only a matter of seconds before the drug is delivered to the blood in the left ventricle and from there to the blood vessels and tissues of the entire body. The nicotine causes dilation of the blood vessels. In an addict deprived of smoking long enough for the drug effect to wear off, the blood vessels constrict, causing discomfort and anxiety. A few puffs administers enough drug to overcome the constriction, discomfort and anxiety. This is the positive reenforcement that teaches the smoker to crave the next cigarette. Other elements of the smoke or the smoking process may also contribute to the addictive process such as the feel of the smoke or other drugs we are not aware of. They may also promptly satisfy the craving of the smoker anxious for the next smoke.
Positive reenforcement strengthens an addiction. It is well known that habits and addictions can be overcome by a process of negative reenforcement or operant conditioning. For example, a patient who was seriously ill from uncontrollable hiccups that could not be stopped by any of the conventional methods was completely cured in one session by administering mild electrical shocks after every hiccup. The anticipation of the shock was apparently enough to overcome whatever mechanism was generating the hiccup.
Another patient with serious mental defficiency was biting her hands so badly that she was in danger of losing them. The habit was broken by administering a mild electrical shock every time she put her hand to her mouth.
This process of negative reinforcement or operant conditioning may be effective in breaking the smoking habit.